US Bridges

US 4 Nh 10 over Mascoma River CSX

Good

Grafton County, New Hampshire · 4.3 MI Lebanon T.L. · Structure no. 014400770010700

Built
1945
80 years old, rebuilt 2008
Condition
Good
inspected May 2021
Type
Girder and Floorbeam System
Steel Continuous
Length
383 ft
3 main spans
Daily traffic
13,685
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

US 4 Nh 10 over Mascoma River CSX is a steel continuous girder and floorbeam system carrying US 4 Nh 10 over Mascoma River CSX in Grafton County, New Hampshire. It was built in 1945 and reconstructed in 2008, so it is 80 years old, older than the New Hampshire average of 56.9 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 13,685 vehicles a day, roughly 5% of them trucks, projected to reach 20,253 by 2043. The structure is 383 ft (116.7 m) long and 40 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesUS 4 Nh 10
CrossesMascoma River CSX
Location4.3 MI Lebanon T.L.
RouteCity Street 4
CountyGrafton County
StateNew Hampshire
Coordinates43.63572, -72.29543
Functional classUrban Minor Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2021
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.7 US tons
Inventory rating37.5 US tons

Structure

Structure typeGirder and Floorbeam System
MaterialSteel Continuous
DeckClosed grating
Main spans3
Design loadHS 20
Structure length383 ft (116.7 m)
Longest span150 ft (45.7 m)
Deck width40 ft (12.2 m)
Roadway width31 ft (9.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,685 (2023)
Projected traffic20,253 by 2043
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesRailroad and waterway
Detour if closed5 mi (8 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$314,000 (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was US 4 Nh 10 over Mascoma River CSX built?

It was built in 1945, making it 80 years old in 2025. It was reconstructed in 2008.

What condition is US 4 Nh 10 over Mascoma River CSX in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in May 2021.

How much traffic does US 4 Nh 10 over Mascoma River CSX carry?

About 13,685 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is US 4 Nh 10 over Mascoma River CSX?

The structure is 383 ft (116.7 m) long with a longest span of 150 ft (45.7 m) and a deck 40 ft wide.

Who owns US 4 Nh 10 over Mascoma River CSX?

It is owned by the City or Municipal Highway Agency.